Electric Machine PCB Thermal Path for High-Current Heat Dissipation
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Solution Overview
Problem
Rotary electric machines face challenges in efficiently dissipating heat generated by electronic components due to the increasingly reduced size of components, which affects heat transfer and electrical conductivity, particularly in hermetically sealed machines where space and thermal constraints are stringent.
Innovation Solution
The electric machine incorporates a printed circuit board with a thermally and electrically conductive layer, where electronic components are soldered directly to the conductive layer, and a conductive mass is used in conjunction with vias to facilitate heat transfer to a heat sink, optimizing heat exchange and current distribution across multiple layers of the PCB.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If electronic components are reduced in size to meet compact packaging requirements, then device complexity and space requirements are reduced, but heat dissipation capability and electrical conductivity deteriorate
Solution Approach 1:
The patent transitions from two-dimensional PCB traces to three-dimensional conductive structures. Specifically, it uses thick copper layers (35-70 micrometers) and vertical vias to create multi-layer conductive paths that extend through the PCB thickness, effectively adding a vertical dimension to heat and current distribution. This dimensional change allows compact surface footprint while maintaining substantial conductive cross-section for heat dissipation and electrical conductivity.
Solution Approach 2:
The patent employs composite thermal management structures combining multiple materials with complementary properties. The heat sink assembly integrates aluminum or copper heat dissipation fins, thermally conductive paste or pads, and phase-change materials in some embodiments. This composite approach allows the compact electronic component to access multiple heat transfer mechanisms (conduction, convection, radiation) while maintaining small footprint.
2Area of stationary object
If electronic components are reduced in size for compact packaging, then space utilization improves, but heat transfer surface area and electrical conductivity worsen
Solution Approach 1:
The patent compensates for reduced component size by exploiting the vertical dimension through multi-layer PCB construction. Thick copper pours on multiple layers connected by substantial vias create three-dimensional conductive networks that provide low-resistance current paths despite reduced surface area. This allows compact layout while maintaining reliable electrical connectivity for high-current applications.
Solution Approach 2:
The patent divides the conductive path into multiple segments across different PCB layers, with each layer contributing to the overall current carrying capability. The current is distributed through multiple parallel conductive paths (copper traces, pours, and vias) rather than relying on a single trace, effectively segmenting the current flow to reduce resistance and improve reliability in compact designs.
3Temperature
If heat transfer devices are added to maximize heat exchange, then heat dissipation improves, but device complexity increases
Solution Approach 1:
The patent merges the heat transfer function directly into the PCB structure itself rather than adding separate heat sinks to each component. The PCB incorporates thick copper layers and thermal vias that serve dual purposes: electrical connectivity and heat conduction. This integration eliminates the need for additional heat transfer devices in many cases, reducing structural complexity while maintaining effective heat dissipation.
Solution Approach 2:
The PCB's conductive structures serve multiple functions simultaneously: they provide electrical current paths, mechanical support, and thermal conduction pathways. The thick copper layers and vias that enable high-current transmission also act as heat sinks and thermal conduction paths, eliminating the need for dedicated heat transfer components and reducing overall device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively disperses heat and manages high currents despite the compact size of electronic components, improving the performance and reliability of the electronic module by minimizing heat concentrations and electrical resistance, while allowing for more efficient use of space on the PCB.
Implementation Method 1
a printed circuit board, or PCB, made up of a plurality of layers and having a top face designed to receive the electronic components of the electronic module itself; this face is also called the component side. The PCB has, on the component side of it, a thermally and electrically conductive layer
Implementation Method 2
a printed circuit board, or PCB, made up of a plurality of layers and having a top face designed to receive the electronic components of the electronic module itself; this face is also called the component side. The PCB has, on the component side of it, a thermally and electrically conductive layer
Implementation Method 3
a heat sink for dissipating the heat generated by the electronic module
Data Source
AI summary
An electric machine includes a casing, a cap covering the casing to define an enclosure, a heat sink, a circuit board in the enclosure having a first conductive layer as a top face, a second conductive layer as a bottom face, and vias passing through the circuit board between the top and bottom faces. An electronic component is soldered to the circuit board on the first conductive layer and disposed on top of a first part of the vias. A conductive mass is soldered to the circuit board proximal to the electronic component and disposed on top of a second part of the vias. The conductive mass forms part of the circuit through which a power supply of the electric machine flows and is in electric and heat exchange relationship with the electronic component, while the bottom face is in heat exchange relationship with the heat sink.